ccx client roaming and 11k with Intel 8260 wifi client

[BelSkorpio]

Hi,

I was wondering how ccx (v4) client roaming and 11k assisted roaming are working together on Cisco 5520 WLC version 8.5.135.0.

Because the roaming decision remains at the client level, I guess that it depends on the client.

Our wifi clients are Intel 8260 based.

What takes precedence ? Is the client going to make its roaming decision based on the CCX neighbor lists or on the 11k neighbor lists ? Or both ?

[Leo Laohoo]

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@BelSkorpio wrote:

I guess that it depends on the client.

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Not only it depends on the wireless client but it also depends on what version is the wireless NIC drivers running on.  The older the version, particularly the ones that came fresh from the factory, the worst roaming performance.

This is why I always recommend people to first upgrade the wireless NIC and then observe if the firmware upgrade makes any changes. 

Another thing, Intel also have a feature called "Aggressive Roaming".  Default value is "2".  When the firmware gets upgraded, push this up to "3".  

And no, pushing up "Aggressive Roaming" without doing any firmware upgrade WON'T WORK.

[BelSkorpio]

My question was rather academic.

Who knows more about it ?

Which neighbor list gets precedence and how do both neighbor lists work together ?

[Dennis Bland · Accepted solution]

As others have pointed out, when the Cisco AP advertises support for both CCXv4 and 802.11k (e.g. Beacon/Neighbor/Link Report capability in RM IE), the client decides which method to use.  

In our experience, CCX would be used in legacy 802.11 modes (802.11a/b/g) as it is a mature protocol with a well-designed test plan and certification process to ensure vendor compatibility.  However, in newer 802.11 modes (802.11n/ac/ax), 802.11k/r/v would take precedence.  Having said that, Intel recently withdrew support for CCX in some of their chipset drivers.  

[BelSkorpio]

Thanks for the reply, Dennis.

It sounds logical to me.

For our Intel 8260 wifi clients, we configure on the Cisco WLC in the client roaming settings a Scan Threshold of -85 in order to eliminate the CCX client roaming and have the roaming purely done on 11k basis. It seems to work fine for us.

We use it in outside wifi environments on port terminals with a lot of APs mounted in light masts.